join

问题 My problem is the following: Lets say I have an existing dataframe with the following columns: UID, foo, result. Result is already partially filled. A second model now predicts additional rows, generating a second dataframe containing a UID and a result column: (Code to reproduce at bottom) ## df_main ## UID foo result ## <dbl> <chr> <chr> ## 1 1 moo Cow ## 2 2 rum <NA> ## 3 3 oink <NA> ## 4 4 woof Dog ## 5 5 hiss <NA> ## new_prediction ## UID result ## <dbl> <chr> ## 1 3 Pig ## 2 5 Snake I

问题 I have the following 2 data tables: DT1 <- data.table(A = c(100,50,10), B = c("Good","Ok","Bad")) DT1 A B 1: 100 Good 2: 50 Ok 3: 10 Bad and DT2 <- data.table(A = c(99,34,5,"",24,86)) DT2 A 1: 99 2: 34 3: 5 4: 5: 24 6: 86 What I would like to return when joining DT1 and DT2 is DT2 A B 1: 99 Good 2: 34 Ok 3: 5 Bad 4: NA 5: 24 Ok 6: 86 Good The "roll" option in data.table is only for "nearest" match so it doesnt work in my case. Is there any way I can do such lookup with data.table? 回答1: The

问题 trying to write a mysql query and having a lot of difficult with this one. I have two tables( Item: info about items, and itemReview: reviews for the items ) What I would like to do is select all the items that belong to a particular location (which is what my outer query does) and then for each item in the outer query, get the average of all the rating fields in the itemReview table Here is my attempt: SELECT Item.idDish, Item.dateAdded, Item.dateModified, Item.fidLocation, Item.category,

问题 Has anyone ran into an issue where all members of the Google Beta Group are able to get the beta version no problem except one. This one user -- who has a valid gmail address -- has joined the Google Grouped used for the beta testing. As the admin I can see they have the status of member . When they click the URL provided for everyone to join the beta for the given application they get a message: I removed them from the group after there were issues and then invited them again. This time I

问题 Has anyone ran into an issue where all members of the Google Beta Group are able to get the beta version no problem except one. This one user -- who has a valid gmail address -- has joined the Google Grouped used for the beta testing. As the admin I can see they have the status of member . When they click the URL provided for everyone to join the beta for the given application they get a message: I removed them from the group after there were issues and then invited them again. This time I

问题 I’ve devised a solution to lookup values from multiple columns of two separate data tables and add a new column based calculations of their values (multiple conditional comparisons). Code below. It involves using a data.table and join while calculating values from both tables, however, the tables aren’t joined on the columns I’m comparing, and therefore I suspect I may not be getting the speed advantages inherent to data.tables that I’ve read so much about and am excited about tapping into.

问题 I’ve devised a solution to lookup values from multiple columns of two separate data tables and add a new column based calculations of their values (multiple conditional comparisons). Code below. It involves using a data.table and join while calculating values from both tables, however, the tables aren’t joined on the columns I’m comparing, and therefore I suspect I may not be getting the speed advantages inherent to data.tables that I’ve read so much about and am excited about tapping into.

问题 I am doing full outer join on 4 tables on the same column. I want to generate only 1 row for each different value in the Join column. Inputs are: employee1 +---------------------+-----------------+--+ | employee1.personid | employee1.name | +---------------------+-----------------+--+ | 111 | aaa | | 222 | bbb | | 333 | ccc | +---------------------+-----------------+--+ employee2 +---------------------+----------------+--+ | employee2.personid | employee2.sal | +---------------------+--------

问题 I am trying to create a MySQL query to return the sum of all statement balances for each account in my DB. The query looks like this: SELECT SUM(balance), handle FROM statement_versions INNER JOIN statements ON statement_versions.statement_id = statements.id INNER JOIN accounts ON statements.account_id = accounts.id; When I do this, it returns only one row with one summed balance and one account (account with ID 1). What I want is to return all accounts with their summed statement balance.

问题 I have 2 dataframes das <- data.frame(val=1:20, type =c("A","A","A","A","A","A","B","B","B","B","B","B","B","B","B","B","C","C","C","C"), weigh=c(20,22,23,32,34,54,19,22,24,26,31,34,36,37,51,54,31,35,43,45)) mapper <- data.frame(type=c("A","A","A","A","B","B","B","B","C","C","C","C"),start = c(19,23,27,37 ,17,25,39,50, 17,23,33,39),end = c(23,27,37,55 ,25,39,50,60, 23,33,39,48)) The expected output is val type weigh labelweight 1 1 A 20 A_19 2 2 A 22 A_19 3 3 A 23 A_23 4 4 A 32 A_27 5 5 A 34